Electrical generators may be used in power plants, cogeneration plants, vehicles, or other implementations for converting mechanical energy into electrical energy. These electrical generators may contain thin sheets of metal, generally called metal laminate structures or “laminations.” Each laminate structure can be stacked to a generator core. A generator core with accompanying laminate structures can be used to create magnetic conductance for power generation. Laminations can also reduce parasitic eddy currents within the generator core. Laminations may serve other purposes as well, such as being thermal conductors and structural supports.
Generally, laminations are cut or stamped from a larger metal sheet of a thin metal coated with “mill coating layers.” Mill coating layers may be composed of ceramic and polymer materials, and are generally provided by a manufacturer of the metal sheet. The mill coating layers can electrically insulate adjacent laminations from each other. Cutting or stamping a lamination from the metal sheet may cause excess metal “burrs” to form along the cut edges of each lamination. The cutting or stamping processes can also damage the mill coating layers, most commonly along the edge of a lamination. Burrs and coating damages are defects which can reduce insulation in the core of a generator.
Typically, any burrs along the edge of a lamination can be removed through additional processes. For example, burrs can be removed from a combination of sanding and grinding. In situations where the metal sheet and its mill coating are especially thin, the risk of damage from deburring can increase. In particular, conventional deburring processes may further damage or even remove the mill coating layers on the lamination. As a result, the laminations may require recoating.